No more black iron?

[hanleyclifford]

The problem with using stainless steel for exhaust is that it sets up a galvanic cell with it being the cathode (more noble) and the first piece of steel or cast iron going to the manifold becoming the anode (less noble) - hence the failure of the steel adapter. Be happy it was just the adapter which is easily replaced. I would still be worried about mixing metals in the presence of salt water which is always being injected into the system.

[joe_db]

I was wondering about that. What if you put a zinc on there somehow?
Meanwhile, I think I'll make another exhaust and swap them out 3-4 years from now instead of waiting for it to leak again. I am a bit frustrated that the original iron exhaust lasted over a decade, they seem to keep getting worse and worse.

[sastanley]

Slightly unrelated, I rebuilt the support structure for the swim platform on my powerboat, which is built out of the same SS pipe as a bimini is made of. I put a zinc on each leg that goes underwater and connects to the bronze fitting bolted to the hull.

[ndutton]

Well done Shawn. The key component = being immersed in an electrolyte.

[Mo]

Slightly unrelated, I rebuilt the support structure for the swim platform on my powerboat, which is built out of the same SS pipe as a bimini is made of. I put a zinc on each leg that goes underwater and connects to the bronze fitting bolted to the hull.

I see your boat Shawn and the name...well I think of "Dock Holiday"...no disrepect intended being on a dock, but it has a ring to it.

[sastanley]

Well done Shawn. The key component = being immersed in an electrolyte.

Neil, When we bought this boat in July 2022, and then hauled it in Dec 2022, there were no zincs left anywhere on the boat, except some small nodules on the trim tabs. There had been two on each prop shaft, a pancake on each rudder, and a pancake on each trim tab.
I asked the previous owner how often he replaced the zincs..
His response.. "When did you buy the boat..July??? That is about the time I would get my dive gear on and put new zincs on everything after launching in March".

I said, "OK, thanks for the info", thinking he just thought that was normal and was putting band aids on a problem. I know more zincs are NOT the permanent answer if he was rolling thru them from March to July, and there is more at play. However, those zincs on the swim platform I can see from the dock, so I have a little piece of mind...however, they are not bonded to other parts of the boat. (as far as I know, nothing on this boat is bonded...that is an entirely different discussion. ) I do not know if the previous owner shore power was suspect, etc. etc. blah blah blah...but I will get to the bottom of it. I need to short haul here at the end of the season for some answers. The boat is in a different location, different shore power, (I do not always have the boat plugged in), all that stuff.

Sorry for the hijack.

I see your boat Shawn and the name...well I think of "Dock Holiday"...no disrepect intended being on a dock, but it has a ring to it.

Ha...none taken Mo! We are still looking for a boat name. This is the last picture I remembered to take as I was grinding the transom off. Y'all got to see the cart before the horse in this thread.